CheckTime - Taking the Guesswork Out of Deicing

Airplane de-iced at the airport
Anchorage, Denver, O'Hare, Louisville and Minneapolis, United States

CheckTime is one of Vaisala's premier winter weather decision support products. A feature embedded within the AviCast product, CheckTime offers Airlines an improved decision support tool over the current manual methods to define Holdover times.

During winter precipitation airlines deice and anti-ice the aircraft to ensure safe operation. The deicing step removes any contaminants from the wing and the anti-icing step covers the wing with a protective anti-icing fluid that absorbs the water of any precipitation to prevent it from adhering to the wing of the aircraft. FAA Holdover Tables provide an estimated amount of time the aircraft can be exposed to the present environmental conditions to ensure a safe departure. The Holdover Tables are based on prevailing visibility as a function of precipitation intensity and air temperature, and assume the conditions remain constant. The Holdover Tables are cumbersome for pilots and cause added distraction among other departure procedures. The tables are also at times inaccurate as they do not factor in the changing weather.

Vaisala's CheckTime solution has made that all easier for the pilot. CheckTime uses precision weather measurement equipment on each airport to measure the Liquid Water Equivalent (LWE, the amount of water in the precipitation) and calculates the deicing and anti-icing fluid saturation point using that information. With the help of real-time environmental data, Vaisala is able to provide dynamic decision support information to the pilot via the airline ACARS computer in the cockpit. No more guesswork or complicated extrapolation tables. The pilot now receives CheckTime (one time) that updates once a minute and the pilot is able to maintain awareness of the state of the deicing and anti-icing fluids on the aircraft. CheckTime accounts for all changes in weather affecting the deicing fluid, and updates the CheckTime each minute to accurately reflect the state of the fluid.

Vaisala is currently engaged in an FAA Winter Demonstration for the use of CheckTime with several U.S. based airlines. These five airlines will provide data to the FAA for future authorization and guidance for all airline use.

The fundamental purpose of CheckTime is to improve efficiencies of airlines and reduce unnecessary use of deicing and anti-icing chemicals.


The fundamental purpose of CheckTime is to improve efficiencies of airlines and reduce unnecessary use of deicing and anti-icing chemicals.

As a thought leader in the aviation industry, Vaisala has installed AviCast Stations at some of the largest winter weather airports in the United States: Anchorage Ted Stevens Airport, Denver International Airport, O'Hare International Airport, Louisville International Airport and Minneapolis St. Paul International Airport in support of the FAA Demo. Vaisala is committed to continue building a network of AviCast Stations worldwide as the airline demand increases.

As a member of the SAE International Committee of Deicing Standards, Vaisala has been in an influential role to set the deicing standards for airlines worldwide. We have received positive feedback from the European Airlines on CheckTime as well. Helsinki airport will be installing an AviCast system in early 2014 to support local operations.